/*
   Private data structure used by the GMRES method. This data structure
  must be identical to the beginning of the KSP_FGMRES data structure
  so if you CHANGE anything here you must also change it there.
*/
#pragma once

#include <petsc/private/kspimpl.h> /*I "petscksp.h" I*/

#define KSPGMRESHEADER \
  /* Hessenberg matrix and orthogonalization information. */ \
  PetscScalar *hh_origin;  /* holds hessenburg matrix that has been multiplied by plane rotations (upper tri) */ \
  PetscScalar *hes_origin; /* holds the original (unmodified) Hessenberg matrix which may be used to estimate the Singular Values of the matrix */ \
  PetscScalar *hes_ritz;   /* holds the last full Hessenberg matrix to compute (harmonic) Ritz pairs */ \
  PetscScalar *cc_origin;  /* holds cosines for rotation matrices */ \
  PetscScalar *ss_origin;  /* holds sines for rotation matrices */ \
  PetscScalar *rs_origin;  /* holds the right-hand side of the Hessenberg system */ \
\
  PetscScalar *orthogwork; /* holds dot products computed in orthogonalization */ \
\
  /* Work space for computing eigenvalues/singular values */ \
  PetscReal   *Dsvd; \
  PetscScalar *Rsvd; \
\
  PetscReal haptol;      /* tolerance for happy ending */ \
  PetscInt  max_k;       /* number of vectors in Krylov space, restart size */ \
  PetscInt  nextra_vecs; /* number of extra vecs needed, e.g. for a pipeline */ \
\
  PetscErrorCode (*orthog)(KSP, PetscInt); \
  KSPGMRESCGSRefinementType cgstype; \
\
  Vec     *vecs;           /* the work vectors */ \
  Vec     *vecb;           /* holds the last full basis vectors of the Krylov subspace to compute (harmonic) Ritz pairs */ \
  PetscInt q_preallocate;  /* 0=don't preallocate space for work vectors */ \
  PetscInt delta_allocate; /* number of vectors to preallocaate in each block if not preallocated */ \
  PetscInt vv_allocated;   /* number of allocated gmres direction vectors */ \
  PetscInt vecs_allocated; /*   total number of vecs available */ \
  /* Since we may call the user "obtain_work_vectors" several times, we have to keep track of the pointers that it has returned */ \
  Vec     **user_work; \
  PetscInt *mwork_alloc; /* Number of work vectors allocated as part of  a work-vector chunk */ \
  PetscInt  nwork_alloc; /* Number of work vector chunks allocated */ \
\
  /* Information for building solution */ \
  PetscInt     it;           /* Current iteration: inside restart */ \
  PetscInt     fullcycle;    /* Current number of complete cycle */ \
  PetscScalar *nrs;          /* temp that holds the coefficients of the Krylov vectors that form the minimum residual solution */ \
  Vec          sol_temp;     /* used to hold temporary solution */ \
  PetscReal    rnorm0;       /* residual norm at beginning of the GMRESCycle */ \
  PetscReal    breakdowntol; /* A relative tolerance is used for breakdown check in GMRESCycle */

typedef struct {
  KSPGMRESHEADER
} KSP_GMRES;

PETSC_INTERN PetscErrorCode KSPView_GMRES(KSP, PetscViewer);
PETSC_INTERN PetscErrorCode KSPSetUp_GMRES(KSP);
PETSC_INTERN PetscErrorCode KSPSetFromOptions_GMRES(KSP, PetscOptionItems *PetscOptionsObject);
PETSC_INTERN PetscErrorCode KSPComputeExtremeSingularValues_GMRES(KSP, PetscReal *, PetscReal *);
PETSC_INTERN PetscErrorCode KSPComputeEigenvalues_GMRES(KSP, PetscInt, PetscReal *, PetscReal *, PetscInt *);
PETSC_INTERN PetscErrorCode KSPComputeRitz_GMRES(KSP, PetscBool, PetscBool, PetscInt *, Vec[], PetscReal *, PetscReal *);
PETSC_INTERN PetscErrorCode KSPReset_GMRES(KSP);
PETSC_INTERN PetscErrorCode KSPDestroy_GMRES(KSP);
PETSC_INTERN PetscErrorCode KSPGMRESGetNewVectors(KSP, PetscInt);

typedef PetscErrorCode (*FCN)(KSP, PetscInt); /* force argument to next function to not be extern C*/

PETSC_INTERN PetscErrorCode KSPGMRESSetHapTol_GMRES(KSP, PetscReal);
PETSC_INTERN PetscErrorCode KSPGMRESSetPreAllocateVectors_GMRES(KSP);
PETSC_INTERN PetscErrorCode KSPGMRESSetRestart_GMRES(KSP, PetscInt);
PETSC_INTERN PetscErrorCode KSPGMRESGetRestart_GMRES(KSP, PetscInt *);
PETSC_INTERN PetscErrorCode KSPGMRESSetOrthogonalization_GMRES(KSP, FCN);
PETSC_INTERN PetscErrorCode KSPGMRESGetOrthogonalization_GMRES(KSP, FCN *);
PETSC_INTERN PetscErrorCode KSPGMRESSetCGSRefinementType_GMRES(KSP, KSPGMRESCGSRefinementType);
PETSC_INTERN PetscErrorCode KSPGMRESGetCGSRefinementType_GMRES(KSP, KSPGMRESCGSRefinementType *);

/* These macros are guarded because they are redefined by derived implementations */
#if !defined(KSPGMRES_NO_MACROS)
  #define HH(a, b)  (gmres->hh_origin + (b) * (gmres->max_k + 2) + (a))
  #define HES(a, b) (gmres->hes_origin + (b) * (gmres->max_k + 1) + (a))
  #define CC(a)     (gmres->cc_origin + (a))
  #define SS(a)     (gmres->ss_origin + (a))
  #define GRS(a)    (gmres->rs_origin + (a))

  /* vector names */
  #define VEC_OFFSET     2
  #define VEC_TEMP       gmres->vecs[0]
  #define VEC_TEMP_MATOP gmres->vecs[1]
  #define VEC_VV(i)      gmres->vecs[VEC_OFFSET + i]
#endif
